Illegitimate get a place in Burke's revolution: Bible of the blue-blooded takes a step into the 21st century

It is the bible of the aristocracy... and has barely changed over the 173 years since it was first published.

But Burke's Peerage and Gentry is finally succumbing to the demands of the 21st century.

The guide, which lists the genealogy of every royal and aristocratic family in the Europe and the U.S., is to include illegitimate children for the first time.

As part of a major shake-up, the book will also list offspring in order of when they are born, rather than males first, which has been tradition.

Over the next few months the records of one million upper class families will be carefully updated to bring them in line with the modern format. The overhauled version, which will be published later this year, will see major changes to the Queen's entry.

Her only daughter Princess Anne is currently listed at the bottom of her four children but in the new version she will be placed behind Prince Charles, who is older, but ahead of Princes Andrew and Edward, who are younger.

George V's entry will be changed to bring his daughter Victoria, known as Mary, up to third from her present last place on the list.

Burke's has previously listed male children first because they were deemed more important, and because most titles are passed down the male line.

The changes will also see the inclusion of one of David Cameron's ancestors, Elizabeth Fitzclarence, the illegitimate daughter of King William IV, who reigned between 1830 and 1837.

The Conservative Party leader is believed to be her fourth great grandson. The changes have been brought in by William Bortrick, the publication's executive and royal editor who at 33 is the youngest person ever to hold the post.

Burke's Peerage, which is published annually, has documented the ancestry of the United Kingdom and Ireland's titled and landed families since 1826. The presidential families of the United States and the royal families of Europe are also included.

Mr Bortrick said the tradition behind the book meant that it adapted slowly to change. But he said he wanted to be more 'inclusive and up to date'.

Announcement: Executive & Royal editor of Burke's Peerage, William Bortrick, took the decision

Burke's is the definitive guide to the genealogical history of the major royal, aristocratic and historical families of the UK, Ireland, Europe and the United States of America.

There are over a million names listed in its records and updating them is a huge task that will take years.

Burke's in future will also list the children of a titled person even if their spouse's family are not in the book.

The changes are being introduced into the online version and will appear for the first time in a printed book when Burke's Royal Families of Europe is published later this year.

Mr Bortrick conceded that the weight of tradition meant changes came slowly at Burke's, but he was keen to be more inclusive and up-to-date.

Since it began in 1826 Burke's has always put the male children first because they were deemed more important and most titles go down the male line.

But now even Burke's finds that anachronistic and despite objections from traditionalists the changes have been approved.

'These really are momentous changes, but they will bring Burke's into the 21st century,' Mr Bortrick said.

'Genealogy is now a subject for everyone from every walk of life and not just for the elite.

'Whether your name is Smith, Jones or Windsor we are all far more connected now.

'Most historic titles are male only, but some go through the female line - and through the last 1,000 years we have had some very strong female figures.

'Just look at the monarchy itself. I don't think British people will have any problem with us listing children in order of when they were born.'

In the updated version, Queen Elizabeth's daughter Anne will be listed behind eldest child Charles, but ahead of Andrew and Edward. Previously she had always been at the bottom of the list.

Mr Bortrick said today many people from titled families did not marry, referring to the decision to list illegitimate children.

'It is just common sense to list their children. Although we would probably not list them if there was a scandal or anything.

'And we will also list the children of those people who marry into a family that is not already listed.

He said the website was getting more hits from 'ordinary people wanting create family trees and do research'.